After allowing the issue to raise some serious questions about his campaign, Mitt Romney told Fox News yesterday that he will release his 2010 tax return tomorrow, along with “an estimate” for 2011. The former governor seems to believe this should put the matter to rest. That strikes me as overly-optimistic.

Such a limited amount of disclosure just isn’t good enough. When Barack Obama ran in 2008, he released returns for the previous eight years. When Bill Clinton ran in 1992, he disclosed 12 years. As we were reminded last week, when George Romney ran, he also released 12 years of returns. He said at the time, “One year could be a fluke, perhaps done for show.”

When pressed on this yesterday, Romney argued his father’s appreciation for transparency came “before the Internet.” I’m not sure exactly what that’s supposed to mean, though it’s probably worth noting that the existence of the Internet didn’t stop the 2008 candidates from being far more forthcoming.

Regardless, David Cay Johnston makes a compelling case today that the controversy will continue to dog Romney “unless he makes public all of his returns from 1984 through 1999.” In other words, there should be scrutiny of Romney’s Bain-era finances.

Unless he releases the tax returns from his Bain Capital years he will surely be pressed about how much, if any, of his fortune has yet to be taxed and how long he deferred paying on the portion that has been taxed. He will be asked about Bain accounts in the Cayman Islands, Bermuda and other tax havens. While perfectly legal, these offshore accounts convey an unsavory political whiff to many people, including some of his rivals for the Republican presidential nomination.

And what about taxes on the $100 million that Romney put into a trust for his five sons. How much Massachusetts and federal income tax, as well as gift tax, was paid on that money?

None of these questions can be answered without the returns from his Bain years.

Romney appears to be counting on the media having a limited attention span. He’ll release his 2010 returns, tell reporters he’s done what he’s been asked to do, and wait for the questions to simply go away.

Here’s hoping they don’t.

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Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.